Many operations performed today involve the use of complex surgical machines. Computerized equipment is often used by surgeons in the operating room (OR) to conduct surgery. These machines monitor and implement various stages of an operation. For example, in ophthalmic surgery, computerized machines and associated tools are used by a surgeon to perform cataract removal and lens replacement. Other machines are used to perform retinal surgery. These machines allow the surgeon to proceed through the steps of an operation.
Most surgical machines are designed to work with various tools. In ophthalmic surgery, these tools include probes, scissors, hand pieces, illuminators, lasers, and consumables. These tools are designed to connect to the front console of the surgical machine. For example, a surgeon performing retinal surgery may attach a small pair of pneumatically driven scissors to the machine. The scissors, in the form of a hand piece, are connected to a pneumatic connector on the front console of the machine with a cable. The cable provides the pneumatic power required to operate the scissors. One end of the cable is attached to the scissors while the other end has a connector designed to couple with the pneumatic connector on the front console of the machine.
Typically, the front console of the machine has a number of connectors designed to connect with and power various tools. For example, one connector may be designed to provide pneumatic power to a tool while another connecter may be designed to provide electric power to a different tool. In addition, a single pneumatic connector on the front console may be designed to interface with a number of different pneumatically-driven tools. Each tool that is plugged into the pneumatic connector will perform its intended function. One tool may be a pair of scissors used to cut tissue. Another tool may be a type of probe or a drug delivery device. Since each of these tools is designed to connect with the pneumatic connector on the console of the surgical machine, each is driven by the pneumatic power supplied by the machine.
A problem can arise during surgery when the wrong tool is connected to the machine. In such a case, the tool operates normally, but the wrong procedure is performed on the patient. For example, a surgeon may mistakenly attach a pair of pneumatically-driven scissors to a machine when he intends to attach a pneumatically-driven drug delivery device. The scissors will perform their intended function of cutting tissue. Since the surgeon intended to deliver a dosage of a drug, however, the unwanted cutting performed by the scissors can injure the patient.
As another example, there may be two different types of cutting tools. Each one may interface with the same connector on the front console of the machine. Using the wrong cutting tool can inflict unintended harm on the patient. Further, there may be two different types of electrically-driven tools, such as an illuminator and a laser. Using a laser when an illuminator is required can harm the patient. In sum, error on the part of the surgeon in using the wrong tool or the wrong type of tool can unintentionally injure a patient during an operation.
Further confusion can occur because of the labeling present on the front of a surgical machine. In conventional surgical machines, the connectors on the front console are passively labeled. A pneumatic connecter designed to work with several different tools may be labeled with a single icon, symbol or LED. This passive labeling may identify the type of connector or that power is being delivered through the connector, but such labeling is ineffective at preventing surgeon error.
In order to address this problem, some conventional surgical machines employ a set of different connectors for a set of different tools. In this manner, each tool is designed to mate with its own connector. However, this configuration of numerous different connectors can be confusing to the surgeon and adds additional expense and complexity to the design of the surgical machine. Moreover, different versions of the same type of tool may interface with a single one of the connectors on the front console of the machine. For example, two different types of scissors may be adapted to fit the same pneumatic connector on the front console of the machine. Using the wrong type of scissors might harm the patient.
Machines with conventional connectors also do not allow the collection of data from the tool. Since the physical connector on the front of the machine is often dumb, it cannot tell which tool is connected to it. Conventional connectors are adapted simply to provide the correct electric or pneumatic power to a tool. These connectors cannot discern what type of tool is connected to them. They also cannot identify a particular tool, how many times a particular tool was used, and other information about how the tool is operating or even if it is operating properly.
A smart connector system for a surgical machine is needed to address these problems. Patent application Ser. No. 11/491,068 filed Jul. 21, 2006, co-owned by applicant, describes such a system. In developing this system, it was discovered that a particular RFID illumination ring configuration overcomes additional problems.
An RFID system consists of two basic parts: an RFID reader and an RFID tag. The RFID reader typically includes a reader antenna, a transceiver, a microprocessor, a power supply, and signal conditioning circuitry. The RFID tag typically includes a tag antenna and an RFID label integrated circuit (IC). An RFID system allows data from the tag to be read by the RFID reader. In a typical RFID system, individual objects are equipped with a small, inexpensive tag. The tag contains an IC with memory to store information. This information is typically a unique code or some other other identifier. The RFID reader emits a signal activating the RFID tag so it can read and write data to it. When an RFID tag passes through the electromagnetic field emitted by the RFID reader, it detects the reader's activation signal. The reader then decodes the data encoded in the RFID tag's IC.
In one type of RFID system, a passive RFID system, the RFID tag does not have an internal power supply. Instead, the passive RFID tag relies on the electromagnetic field produced by the RFID reader for its power. The electromagnetic field produced by the RFID reader induces an small electrical current in the tag antenna. This small electrical current allows the tag IC to operate. In this passive system, the tag antenna is designed to both collect power from the electromagnetic field of the reader and to transmit an outbound signal. Passive tags have practical read distances ranging from about 2 mm up to a few meters depending on the chosen radio frequency and the size and shape of the antenna.
Semi-passive and active RFID tags have their own source of power. A semi-passive RFID tag typically uses a small battery for its power supply. Active RFID tags typically have an on-board power supply. The power provided by these sources allows a tag to perform additional functions.
Regardless of which type of RFID system is chosen, the closer the tag antenna is to the reader antenna, the better the system performs. Since the strength of an electromagnetic field emitted from an antenna decreases in proportion to the square of the distance from the antenna, it is desirable to have the tag antenna close to the reader antenna.
The reader antenna typically resides on a printed circuit board (PCB). To improve performance of the RFID system, it is desirable to place the PCB with the reader antenna close to the tag antenna. The tag antenna, however, is located on an item that is separate from and movable with respect to the PCB with the reader antenna. In the context of a surgical machine, the PCB with the reader antenna resides in the main console while the tag IC and tag antenna reside on a peripheral, such as a tool, that can be connected to the console of the surgical machine. It would be desirable to locate the PCB with the reader antenna close to the front panel of the surgical machine in a location close to where the tool attaches. The tag antenna can be located on the mating connector of the tool. When the mating connector of the tool is plugged into the connector on the front panel of the machine, the reader antenna and the tag antenna can be located very close to each other.
In a surgical machine with an illumination ring system, it would be desirable to locate the light emitting diodes (LEDs) that provide the light for the illumination ring on the same PCB that has the reader antenna. Having a single PCB for both the RFID reader and ring illumination functions reduces the number of parts needed to build the machine.
Traditionally, an illumination ring is a separate component implemented using a light pipe. A typical light pipe has multiple parts that complicate assembly during the manufacturing process. A light pipe also requires custom tooling. A light pipe can also be too long to fit in tight places, such as the space between the manifold and the front panel on a surgical machine. Another alternative that is traditionally employed is a light diffusing ring assembly. A light diffusing ring assembly also consists of separate parts that complicate assembly during the manufacturing process, requires more power, and utilizes relatively expensive LEDs.
It would be desirable to have an illumination ring incorporated into the front panel of a surgical machine with LEDs located on a PCB. Incorporating the illumination ring into the front panel would decrease the complexity of assembly during the manufacturing process and provide a smooth front panel surface that is less likely to trap dirt and germs. The fewer seams on the front panel of a surgical machine, the better for reducing the possiblility of contamination in an operating room. Since the surgical machine is located in an operating room, it is desirable to keep it clean to reduce the risk of infection. In addition, it would be desirable to have the RFID reader antenna on the same PCB that carries the LEDs. Having both the RFID reader antenna and the LEDs to light the illumination ring on the same PCB decreases the number of components needed and decreases the complexity of assembling a surgical machine.